Taylor U.S. Pat. No. 3,971,250 describes a sensing transducer comprising a plurality of electric layers formed from materials having both pyroelectric and piezoelectric characteristics, such as polyvinylidene fluoride (PVF.sub.2). The medium layer can be bent about the longitudinal midpoint of an insulative layer by selective application of a charge.
Croswell, Jr. U.S. Pat. No. 3,885,758 discloses an arrangement for controlling the angular configuration of a fluid controlled surface by selectively controlling the expansion and contraction of a plurality of structural wires in the upper and lower skin of an airplane wing. The device contemplates the use of various composite materials which will contract or restrict when subjected to an electrical current. Also, the structural elements that will expand or contract to produce the curvature of an aerodynamic surface may be constructed of an electrostrictive material, such as crystalline barium titanate ceramic.
Croswell, Jr. U.S. Pat. No. 3,930,626 discloses the use of structural wires employed to control the angular configuration of a fluid control system. According to the patent the structural elements that will expand or contract to produce curvature of the aerodynamic surface may include piezoelectric materials.